I currently have a 29g that has been going for two years. The tank has crushed coral on the bottom, I have around 40 pounds of live rock, a mushroom coral, Brain Coral, and several dead corals mixed in. I also have a Maroon Clown, Blue Damsel, Coral Banded shrimp, brittle star and some snails and blue legged hermits. I feed one time a day, sparingly. My problem is I can not get my nitrate (no3) to go down. I have a penguin biowheel filter , a seclone protein skimmer, and two swivel powerheads. I have changed 4 to 5 gallons every other week for the last three months. I can not get my nitrates under 80ppm. I heard if you have crushed coral, you always have nitrate problems. I would like to switch from crushed coral to a sandbed. Is there anyway I can do this safely without striping my Tank and starting over???